content: /**
   * Copyright (c) 2016-present, RxJava Contributors.
   *
   * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
   * compliance with the License. You may obtain a copy of the License at
   *
   * http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software distributed under the License is
   * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
   * the License for the specific language governing permissions and limitations under the License.
   */
  
  package io.reactivex.observable.internal.operators;
  
  import java.util.concurrent.atomic.AtomicBoolean;
  
  import io.reactivex.common.*;
  import io.reactivex.common.disposables.CompositeDisposable;
  import io.reactivex.common.exceptions.Exceptions;
  import io.reactivex.observable.*;
  import io.reactivex.observable.internal.disposables.EmptyDisposable;
  
  public final class SingleAmb<T> extends Single<T> {
      private final SingleSource<? extends T>[] sources;
      private final Iterable<? extends SingleSource<? extends T>> sourcesIterable;
  
      public SingleAmb(SingleSource<? extends T>[] sources, Iterable<? extends SingleSource<? extends T>> sourcesIterable) {
          this.sources = sources;
          this.sourcesIterable = sourcesIterable;
      }
  
      @Override
      @SuppressWarnings("unchecked")
      protected void subscribeActual(final SingleObserver<? super T> s) {
          SingleSource<? extends T>[] sources = this.sources;
          int count = 0;
          if (sources == null) {
              sources = new SingleSource[8];
              try {
                  for (SingleSource<? extends T> element : sourcesIterable) {
                      if (element == null) {
                          EmptyDisposable.error(new NullPointerException("One of the sources is null"), s);
                          return;
                      }
                      if (count == sources.length) {
                          SingleSource<? extends T>[] b = new SingleSource[count + (count >> 2)];
                          System.arraycopy(sources, 0, b, 0, count);
                          sources = b;
                      }
                      sources[count++] = element;
                  }
              } catch (Throwable e) {
                  Exceptions.throwIfFatal(e);
                  EmptyDisposable.error(e, s);
                  return;
              }
          } else {
              count = sources.length;
          }
  
          final CompositeDisposable set = new CompositeDisposable();
  
          AmbSingleObserver<T> shared = new AmbSingleObserver<T>(s, set);
          s.onSubscribe(set);
  
          for (int i = 0; i < count; i++) {
              SingleSource<? extends T> s1 = sources[i];
              if (shared.get()) {
                  return;
              }
  
              if (s1 == null) {
                  set.dispose();
                  Throwable e = new NullPointerException("One of the sources is null");
                  if (shared.compareAndSet(false, true)) {
                      s.onError(e);
                  } else {
                      RxJavaCommonPlugins.onError(e);
                  }
                  return;
              }
  
              s1.subscribe(shared);
          }
      }
  
      static final class AmbSingleObserver<T> extends AtomicBoolean implements SingleObserver<T> {
  
          private static final long serialVersionUID = -1944085461036028108L;
  
          final CompositeDisposable set;
  
          final SingleObserver<? super T> s;
  
          AmbSingleObserver(SingleObserver<? super T> s, CompositeDisposable set) {
              this.s = s;
              this.set = set;
          }
  
          @Override
          public void onSubscribe(Disposable d) {
              set.add(d);
          }
  
          @Override
          public void onSuccess(T value) {
              if (compareAndSet(false, true)) {
                  set.dispose();
                  s.onSuccess(value);
              }
          }
  
          @Override
          public void onError(Throwable e) {
              if (compareAndSet(false, true)) {
                  set.dispose();
                  s.onError(e);
              } else {
                  RxJavaCommonPlugins.onError(e);
              }
          }
      }
  
  }
  